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Povzetek: 316L stainless steel is widely used in marine and biomedical applications. However, its protective Cr-rich passive film can be destabilized by microbiologically influenced corrosion (MIC). Here, a multidisciplinary approach combining electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), optical profilometry, ATR-FTIR, X-ray photoelectron spectroscopy (XPS), and ICP-OES was used to investigate corrosion behavior and passive film chemistry of 316L stainless steel (SS) exposed to Pseudomonas aeruginosa in artificial seawater, and to evaluate the inhibitory effect of an aqueous Artemisia annua extract (AAE). Exposure to P. aeruginosa, resulted in a marked decrease in film resistance, increased corrosion current density, enhanced Fe dissolution, and pronounced surface pitting. Although biotic exposure increased the apparent oxide thickness, XPS analysis revealed the formation of a chemically heterogeneous and less protective surface layer. In contrast, the addition of AAE significantly mitigated these effects by stabilizing a Cr-enriched passive film, increasing charge-transfer resistance, reducing jcor, and suppressing localized attack. ATR-FTIR confirmed adsorption of phenolic acids from AAE, while XPS depth profiling revealed stabilization and thickening of the passive layer. The inhibition efficiency of AAE, evaluated by PP, EIS, and ICP-OES, ranged from 65% to 83%, demonstrating consistent protective behavior across all methods. These results indicate that A. annua extract acts as a plant-derived corrosion inhibitor that preserves the functional stability of the Cr-rich passive film under MIC conditions, offering a promising strategy for corrosion mitigation in marine environments.
Ključne besede: biofilm formation, electrochemical impendance spectroscopy, seawater corrosion, ATR-FTIR spectroscopy, X‑ray photoelectron spectroscopy, passive film stability
Objavljeno v DiRROS: 20.03.2026; Ogledov: 151; Prenosov: 113
Celotno besedilo (6,59 MB)
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Ključne besede: ODS steels, austenitic steels, corrosion, mechanical properties
Objavljeno v DiRROS: 02.03.2026; Ogledov: 216; Prenosov: 170
Celotno besedilo (29,65 MB)
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Povzetek: The impact of oxic and thermal transient phases on corrosion of carbon steel in cementitious environment was studied through three in situ experiments (Tournemire URL, France). For two years, heated metallic samples (80 °C) were placed in direct or indirect contact with two different cementitious materials: a low-pH Bentonitic Cement Grout (BCG) and a Portland cement paste material (CEM I). Mineralogical and microstructural analyses were carried out in an attempt to identify the combined effects of pH, chemistry and microstructure properties associated with such specific cementitious media on steel corrosion mechanisms. Additionally, in situ Electrical Resistance (ER) corrosion sensors allowed to continuously monitor the corrosion rates corresponding to each of the three field experiments. Post-mortem characterisation indicated that metallic samples embedded in low-pH BCG were heavily damaged and exhibited high corrosion rate. Conversely, steel samples in contact with highly alkaline CEM I environment appeared to be much less impacted by corrosion processes and revealed extremely low corrosion rate values. A comparison between these field experiments observations and results previously obtained through complementary laboratory mock-up tests finally enabled the evaluation of the impact that variations in geometrical/design aspect existing between in situ and laboratory tests can induce on material degradation.
Ključne besede: bentonitic cement-based grout, deep geological disposal of nuclear waste, anoxic environment, electrical resistance corrosion sensors, groundwater, low-pH cement
Objavljeno v DiRROS: 27.01.2026; Ogledov: 240; Prenosov: 70
Celotno besedilo (1,84 MB)
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Povzetek: The aim of this study was to investigate the interaction between macrocell and microcell corrosion processes in a concrete column exposed to tidal conditions simulated by sinusoidal water-level changes. Macrocell corrosion currents were continuously measured for 19 weeks along the column height using coupled multi-electrodes (CMEs). Cumulative corrosion damage and the morphology of corrosion products were analysed using X-ray microCT, SEM, and Raman spectroscopy. The results showed complex patterns of anodic and cathodic activity, including sinusoidal and switch-like current behaviour, which depended on the water level position and exposure time. Corrosion typically initiated in the upper tidal zone, but the most corroded individual electrode was located near mid-tide. Damage distribution was influenced by both microcell and macrocell corrosion, where microcell corrosion was most prevalent in the high-tide area, whereas macrocell activity contributed to corrosion damage in several exposure zones. SEM and Raman analyses confirmed a correlation between corrosion type and corrosion product morphology. An attempt was made to explain the recognised corrosion patterns along the vertical position and the ratios between microcell and macrocell corrosion on individual electrodes were esti- mated. Additionally, new questions were raised that highlight the complexity of corrosion processes under tidal cycling and emphasise the need for further research into these phenomena.
Ključne besede: corrosion, coupled multi-electrode array, simulated tiding, reinforced concrete, macrocell corrosion
Objavljeno v DiRROS: 12.01.2026; Ogledov: 267; Prenosov: 204
Celotno besedilo (8,38 MB)
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Ključne besede: corrosion inhibition, standard adsorption Gibbs energy, surface coverage, adsorption isotherm
Objavljeno v DiRROS: 10.10.2025; Ogledov: 529; Prenosov: 289
Celotno besedilo (1,85 MB)
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